ID   LEXA_THEAB              Reviewed;         198 AA.
AC   B7IDD1;
DT   14-APR-2009, integrated into UniProtKB/Swiss-Prot.
DT   10-FEB-2009, sequence version 1.
DT   03-AUG-2022, entry version 90.
DE   RecName: Full=LexA repressor {ECO:0000255|HAMAP-Rule:MF_00015};
DE            EC=3.4.21.88 {ECO:0000255|HAMAP-Rule:MF_00015};
GN   Name=lexA {ECO:0000255|HAMAP-Rule:MF_00015}; OrderedLocusNames=THA_1570;
OS   Thermosipho africanus (strain TCF52B).
OC   Bacteria; Thermotogae; Thermotogales; Fervidobacteriaceae; Thermosipho.
OX   NCBI_TaxID=484019;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=TCF52B;
RX   PubMed=19124572; DOI=10.1128/jb.01448-08;
RA   Nesboe C.L., Bapteste E., Curtis B., Dahle H., Lopez P., Macleod D.,
RA   Dlutek M., Bowman S., Zhaxybayeva O., Birkeland N.-K., Doolittle W.F.;
RT   "The genome of Thermosipho africanus TCF52B: lateral genetic connections to
RT   the Firmicutes and Archaea.";
RL   J. Bacteriol. 191:1974-1978(2009).
CC   -!- FUNCTION: Represses a number of genes involved in the response to DNA
CC       damage (SOS response), including recA and lexA. In the presence of
CC       single-stranded DNA, RecA interacts with LexA causing an autocatalytic
CC       cleavage which disrupts the DNA-binding part of LexA, leading to
CC       derepression of the SOS regulon and eventually DNA repair.
CC       {ECO:0000255|HAMAP-Rule:MF_00015}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=Hydrolysis of Ala-|-Gly bond in repressor LexA.; EC=3.4.21.88;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_00015};
CC   -!- SUBUNIT: Homodimer. {ECO:0000255|HAMAP-Rule:MF_00015}.
CC   -!- SIMILARITY: Belongs to the peptidase S24 family. {ECO:0000255|HAMAP-
CC       Rule:MF_00015}.
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DR   EMBL; CP001185; ACJ76008.1; -; Genomic_DNA.
DR   RefSeq; WP_004102298.1; NC_011653.1.
DR   AlphaFoldDB; B7IDD1; -.
DR   SMR; B7IDD1; -.
DR   STRING; 484019.THA_1570; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ACJ76008; ACJ76008; THA_1570.
DR   KEGG; taf:THA_1570; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_1_0; -.
DR   OMA; HVWLLPH; -.
DR   OrthoDB; 1933795at2; -.
DR   Proteomes; UP000002453; Chromosome.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0004252; F:serine-type endopeptidase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0006281; P:DNA repair; IEA:UniProtKB-UniRule.
DR   GO; GO:0006260; P:DNA replication; IEA:UniProtKB-UniRule.
DR   GO; GO:0045892; P:negative regulation of transcription, DNA-templated; IEA:UniProtKB-UniRule.
DR   GO; GO:0006508; P:proteolysis; IEA:InterPro.
DR   GO; GO:0009432; P:SOS response; IEA:UniProtKB-UniRule.
DR   CDD; cd06529; S24_LexA-like; 1.
DR   Gene3D; 1.10.10.10; -; 1.
DR   HAMAP; MF_00015; LexA; 1.
DR   InterPro; IPR006200; LexA.
DR   InterPro; IPR039418; LexA-like.
DR   InterPro; IPR036286; LexA/Signal_pep-like_sf.
DR   InterPro; IPR006199; LexA_DNA-bd_dom.
DR   InterPro; IPR006197; Peptidase_S24_LexA.
DR   InterPro; IPR015927; Peptidase_S24_S26A/B/C.
DR   InterPro; IPR036388; WH-like_DNA-bd_sf.
DR   InterPro; IPR036390; WH_DNA-bd_sf.
DR   Pfam; PF01726; LexA_DNA_bind; 1.
DR   Pfam; PF00717; Peptidase_S24; 1.
DR   PRINTS; PR00726; LEXASERPTASE.
DR   SUPFAM; SSF46785; SSF46785; 1.
DR   SUPFAM; SSF51306; SSF51306; 1.
DR   TIGRFAMs; TIGR00498; lexA; 1.
PE   3: Inferred from homology;
KW   Autocatalytic cleavage; DNA damage; DNA repair; DNA replication;
KW   DNA-binding; Hydrolase; Reference proteome; Repressor; SOS response;
KW   Transcription; Transcription regulation.
FT   CHAIN           1..198
FT                   /note="LexA repressor"
FT                   /id="PRO_1000192779"
FT   DNA_BIND        28..47
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        120
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        157
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            84..85
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   198 AA;  22460 MW;  3D0419FB72C906D3 CRC64;
     MKELTNRQKM VLDFITSYIQ QNGYSPSIRD IAKHFKLTPR GAHIHVLALE KKGYITRNPK
     NSRSISLVKR PETVSIPVKG KISAGQGIEM FELVDEEIEI PVRMINGYGN YFALRVEGTS
     MIEAHIIDGD YVILKKQYRI PNGQIAAVVF DNKVTLKRFY HKNDKVELVP ENSSMSPIIC
     DAKDVKVIGK LVGVIRIY